Summary
Better understanding of risk factors for major bleeding events during anticoagulant
treatment for venous thromboembolism (VTE) may help physicians when deciding on intensity
and duration of treatment. The primary aim of this study was to identify risk factors
for major and clinically relevant bleeding in patients receiving the oral factor Xa
inhibitor edoxaban or warfarin for the treatment of acute VTE. We analysed data from
8240 patients who received ≥1 dose of study drug in the Hokusai-VTE study. Bleeding
risk factors were evaluated in 4118 patients who received edoxaban and significant
variables were combined in a prediction model. We used the C-statistic to estimate
model discrimination and bootstrap techniques for internal validation. Major bleeding
occurred in 56/4118 (1.4 %) patients given edoxaban and in 66/4122 (1.6 %) patients
given warfarin. Clinically relevant bleeding occurred in 349 (8.5 %) and 423 (10.3
%), respectively. Significant risk factors for major bleeding during edoxaban treatment
were female sex, concomitant antiplatelet therapy, haemoglobin ≤10 g/dl, history of
arterial hypertension, and systolic blood pressure >160 mmHg. The discrimination of
the model was high (C-statistic: 0.71) for major bleeding, lower for clinically relevant
bleeding (C-statistic: 0.62) and when the model was applied to patients receiving
warfarin (C-statistic 0.60). In conclusion, we identified five main predictors of
major bleeding in patients receiving edoxaban for the treatment of acute VTE. A risk
model based on these factors predicted an increased risk of bleeding with good discrimination.
Supplementary Material to this article is available online at www.thrombosis-online.com.
Keywords
Anticoagulants - haemorrhage - risk factors - thrombosis - venous thromboembolism